If you're getting the same error on iOS,

1. Open your iOS project in Xcode using this command:

   open ios/Runner.xcworkspace
   
   

2. In Xcode, go to:
   Runner → Signing & Capabilities

3. Check whether Push Notifications capability is added.

   • If it’s missing, click the + Capability button and add Push Notifications.

4. Make sure the capability is enabled for both Debug and Release modes.

   • In my case, it was only enabled for Debug, and that caused the error.

   • After enabling it for Release as well, everything started working correctly.

Hope this helps you too!